Research On Privacy Protection And Sharing Methods Of Cloud Data In Blockchain Environment

With the rapid development of computer technology,electronic data stored in digital form is constantly emerging,reducing the consumption of paper documents,greatly simplifying the process of data storage and transmission,improving the data accuracy and productivity of users.Under normal circumstances,electronic data relies on third-party cloud servers for data storage or sharing,which eases the burden on users,but problems such as privacy leaks,data transmission delays,malicious node attacks,and data tampering may occur.As an emerging decentralized technology,blockchain has attracted more and more attention due to its distributed storage,anti-tampering and anonymity features,which can effectively alleviate data tampering problems and node attack problems caused by cloud servers.As the requirements for data privacy protection and sharing gradually increase,it is necessary to find a way to enable electronic data to be stored and shared safely and efficiently in an open and transparent blockchain.To this end,this paper deeply studies the methods of electronic data storage and sharing in the context of blockchain and cloud,combined with characteristics of cryptography and edge computing.The main work carried out includes:Firstly,aiming at the weak access control problem and difficult permission revocation problem of cloud data,a privacy protection method of separation of public and private encryption of cloud data in the blockchain environment is proposed with the medical environment as an application scenario.This approach separates the public and private parts of the electronic medical record,encrypts each part separately using symmetric searchable encryption technology,and encrypts the symmetric keys used separately using attribute-based encryption technology,which ensures better fine-grained access control.At the same time,a mechanism for permission granting and revocation of electronic medical record is designed in a dual-chain environment,where smart contract is used to verify the attribute set with the nearest timestamp to decide whether to revoke or grant access by updating the attribute set through a trust authority,improving the incompatibility between the tamper-proof features of the blockchain and the revocation of permissions in attribute-based encryption technology.Secondly,on account of the non-single trust domain problem and task processing congestion problem in edge computing,a privacy protection method of cloud data based on edge computing trust computing in blockchain environment is proposed.The method designs a group agent policy based on trust calculation,where trust is evaluated based on certain criteria after interaction within the group,and the device with the highest average weighted trust value is set as the group agent to help the whole group upload or request data to the edge node,while devices with average weighted trust value below a certain threshold are kicked out of the group.This method utilizes the Delaunay triangle network and Voronoi diagram to determine the location of edge nodes,ensuring all edge devices in the region are closer to the edge node in the same region than the edge nodes in other regions.Finally,a staggered mechanism has been introduced to distribute tasks rationally within a time period to avoid system blockages.Thirdly,specific to the low data search efficiency problem and unreasonable resource allocation problem in edge computing,a sharing method of cloud data based on edge computing resource allocation in blockchain environment is proposed.In this method,a stack task ranking mechanism is designed.By matching task stacks and address stacks,the tasks with high urgency can be processed by the server with many resources.A new content model was created using Zipf distribution to predict the contextual popularity of keywords.In addition,an optimized consensus algorithm is designed to better verify the authenticity of the index.Fourthly,a hotspot data management system is designed.In the system,a trending topic function is added to the system to focus on the important news in life by updating the hot search data in real time.At the same time,the system matches corresponding edge nodes based on geographic location when searching,reducing both storage pressure on the cloud and query latency for users.Finally,the overall architecture and functional modules of software are designed and displayed according to the functional requirements of the hotspot data management system.In summary,this paper studies the methods of cloud data privacy protection and sharing in the blockchain environment.Through the three methods and the management system proposed in this paper,the security of user privacy protection and the efficiency of data sharing are improved,which has certain reference significance to promote the progress of privacy protection and data sharing.